sadly without a multitude of other items found on same location, there is no way to identify that bell as being part of a military camp. There should be a bunch of other finds that support your theory. camp lead, military related items like buckles, buttons, standard mess kit items, or other things that usually only existed in the military. and you need enough of this stuff to prove it was not just an item or two lost after the war. say if you found a military button and a musket ball, that does not mean military camp. But if you found multiple buttons, camp lead like miscast bullets or trim offs from moulds, buttons, and a buckle or gun sling part and so on, then you might have a camp or skirmish site.